If you play D&D 5e here are a few pdfs that you can use for additional information for your character.  All are fillable. Or mostly fillable.

Equipment Sheet.

Somewhere to note all that equipment and loot you are not worried about carrying because your DM does not bother with encumbrance rules.

DnD 5e Equipment Sheet

Character Notes Sheet.

Somewhere to keep track of people you have met, interesting tidbits of information and so forth.

DnD 5e Equipment SheetDnD 5e Notes

Character Background Sheet.

Somewhere to put all that background information you can generate using Xanathar’s Guide to Everything.

DnD 5e Life Path Sheet