For myself I tend to go with unless I earn it for myself with the sweat of my brow I don't care for it. No morals or anything, just personal preference. Part of said sweat is maintaining systems for people that do want to do such things, and I have got bored and read all their books as well when waiting for percentage bars to crawl up, not to mention if I am helping with investigations it helps to speak the language.
Investing as a general concept then is you take some store of value, trade it for something and hope it appreciates fast enough that you can trade it again and make something from it.
There are of course many ways of doing this.
Some will do with money, indeed for many it is probably their first real introduction to anything active (a savings account is a type of investment but eh). Foreign exchange being the most common. You bet that whatever money you change to another currency will change such that when you convert it back that you have more than you began with (you buy some small African country's currency, they discover some lost civilisation and build a hotel next door, every tourist will want to go there so the demand for that currency goes up and you have a bunch of it, however if they break out in civil war then nobody will want to go and it goes down). Most people don't make a lot in this market and it is very easy to lose your shirt, especially if you use some of the dedicated "forex" platforms. You don't need such a platform -- you can do this at your local supermarket/post office if they have an exchange but chances of you making much of anything with such a setup is low.
Bitcoin was kind of this for a while as well but had some different properties that would want to be discussed (I will spare us that one for now).
Shares.
A huge field.
Most of the stuff you see in cheesy films is big boy share trading, the likes of which you have to have "if sir has to ask" money to even get a foot in the door, even if you have "if sir has to ask" money you may have a hard time (see widows and orphans laws).
Mere mortals can still buy shares but the prices are higher and availability might not be as much, to say nothing of the timeframes. Even the big boys will occasionally group people together for a buy in and there are thousands of formats for this one. If you work for a company you might be given shares, be able to buy them or something similar too, though be careful here as you might have restrictions and you will also want to know what insider trading is (it is considered bad and actually quite illegal in a lot of places despite being something most normal people would consider acceptable in some ways).
If you only have a bit of money to play (50 to 100 grand, possibly up to a million) with then you can hire an investment/wealth management company to either create a portfolio or act as your intermediary. They cost a bit but have access and theoretically some experts that might do better than you, or at least stay ahead of the law. They cost quite a bit (I once knew someone that worked for one -- a client of theirs wanted a printout/photocopy of something, for a ctrl+p and a walk of 5m to the printer cost said client £50. There was me two days before fixing someone's laser printer and coming away looking like a coal miner for less than that) but will allow you to play and you can get to them to act on your behalf too.
There are lesser versions though. Spread betting is a popular one, though for some not a great one. It literally mirrors the stock market (and a few other markets) so you can play like you are a big boy trader, however the cut they take for cashing out is often quite high, enough that if you can do well on such a platform an investment bank will probably come knocking as you have a rare skill. Being as it is technically betting the tax laws also change (I don't know the current stuff but bets were once bets and not really the domain of the tax man). Oh and look what happens if your values go lower than what you "invested" at.
The different regions thing. Companies get together, or in some cases finance companies invite other companies to join, a stock market/stock exchange. All they will do is trade in shares in a given list of companies**, said list might be focused on different things (region, tech, finance, physical items -- oil and gold and physical things after all). New ones might get invited, others might drop out (being delisted is a bad thing for most companies so it usually follows a period of them not doing well). They will have certain hours (see market open and close of market), price in certain currencies and be restricted to certain regulations. Various companies may be on more than one market and said differences may be exploited (classically if say New York closed before London opens then if a share in New York went up massively before London opened, which owing to time differences is often late at night in the UK, you would be prepared to buy as much as you could in London at opening knowing that it would likely go up there as well), though these days there are very fast computers located right next to the financial exchanges to do that for people (this is one aspect of so called high speed trading).
There are many types of shares, and what a company is doing is often information you can see (earnings reports, financial reports, do they have a winning product on the market, are they facing a big lawsuit... Though I should note that most share are only concerned with the next "quarter" -- in games a good example might be Rockstar games. If they release table tennis as their effort for the year then it is not going to sell much and the people that don't know anything about games (most investors don't know anything about anything other than investing) will see low sales and the price will drop, you know however that the next GTA will be out next year and from the previews it is all that and more so you buy when the prices are low and sell them again next year when they are making billions off the next GTA.
**said list will tend to be grouped together into an index, you can then buy into an "index fund" which nominally has interests in all of them. That way if one goes down but everything else goes up you should still be OK. This is one aspect of so called diversification, and one thing one of those expensive firms will try to ensure you have (if a company goes bankrupt then you will likely not be able to sell for what you bought in at, it is rare that hundreds of companies go bankrupt at once, much less across multiple different/unrelated industries, but go look at the list of bankrupt companies and failed ventures -- how many times now has microsoft tried to break into phones/tablets and failed miserably? How many big retail shops have failed?).
Taxes.
Investment is a complex part of tax law and there are a billion workarounds (see offsets) and quirks ranging from tax incentives (shareholders may be only charged 19% tax compared to 20% for normally earned money, hence a lot of people in IT and similar consulting firms, often one man firms, registering as a company, paying themselves a small salary and taking the rest as shareholder payout) to tax limits (see capital gains tax*) and more besides.
*it applies to money investments but many will meet it when selling old furniture or art or whatever that has gone up in value. It can also apply if you buy something, fix it up and sell it on.
Speaking of art
Scalping is a type of investing.
In the end I think I will go with "never invest anything you can't afford to lose".
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