Making changes to stories and items in purchased modules

Hi,

I recently bought a published D&D module for FG, and as I was prepping my campaign, I discovered that I could make changes to the text in the story items and encounters that came with the module. Are any changes that I make only applied to the campaign, or does it permanently change the module for any other campaign? My guess is the former, as the latter would be dangerous. But I want to be certain before I get myself in trouble.

Correct, adventures are editable because GMs frequently want/need to make changes for their campaign, and also correct that those changes only exist within that specific campaign's database; you are not altering the purchased data.