to answer you
@Tinashe and
@Nekikool you have to have Checkpoint,you create a backup and pull it up in PkHex, if you want to get every pokemon you need to input them all seperately as the new pokemon games use .pb7 files and not .pk7 files.
PLEASE MAKE A BACKUP BEFORE GOING AHEAD AND CHANGING YOUR SAVE( AS IN COPY YOUR CHECKPOINT FOLDER FOR YOUR GAME SOMEWHERE SAFE)
ALSO MAKE SURE YOU KNOW HOW TO MOD/HACK PROPERLY WITH YOUR TOOLS AS TO NOT BRICK YOUR CONSOLE( I AM NOT TO BLAME IF YOU STUFF UP)
It took me a while but im done.Some pokemon can't be created for some reason like trading or some other reasons i don't know some didn't work for me.
When modding a pokemon if you change the level you need to click Auto button next to CP( or once you've changed your IVS and EVs aswell),you will then go to the met tab and click on the text met location when creating a new pokemon and it should automatically give you the recommended location,you will then go to the attacks tab and choose the moves that you want(if the move doesnt work it will show a ! icon in a triangle) else you can just click the current moves text and it will show you the recommended moves. If the pokemon show a red ! on it then right click on that square and click set,then click view to try fix it,if it fixes then right click the same square and click set again.
Once your done with inputting every single pokemon single handedly there is a button in the top left there is a button click it and click Export Sav and the first option.You will then replace your save in your checkpoint folder with your exported save. You will then need to go into your checkpoint and your lets go eevee/pikachu and press restore.
You can modify your items and pokedex amongst other things,i suggest when clicking these buttons as when you do you can obtain everything via a single click not to do it,as i think some items are story based,so it might stuff up your game or so,so be careful.
I suggest on PkHex to not change your PID and SID only your money in the trainer tab.
Also do not touch the event flags tab either as if you don't know what your doing you might brick your game or softlock it.
For Pokedex i suggest only changing your pokedex in the top right click modify and click seen all,caught all and complete pokedex. I HIGHLY SUGGEST that you then as some pokemon can't be acquired via PkHex for some reason then to go into that same pokedex tab and find each pokemon you couldn't create and untick each box for each single one.
I hope this has been helpful. Good luck with your editing and as i have said and warned I am not to blame if you stuff up your console or save.