Because this data is not heavily encrypted (unlike some commercial AAA games), it is relatively easy to decode and modify—provided you have the right tool.
Quick, one-off changes without needing any technical knowledge. RPG Maker MV Save Editor (GitHub/Local Tools)
[Link]
Go to the Save Editor Online web tool. Drag your file1.rpgsave into the designated area.
You can modify HP, MP, Attack, Defense, etc. This is great for "god mode" runs or for tweaking a character build that feels underpowered.