What's the recommended way to make changes to files in htdocs?

I thought this would be explained somewhere, but couldn’t find it.

When making any changes in the web site root I have to user sudo. I’d rather not have to. The folder obviously has www-data as the owner, and the group. Adding myself to the www-data group was of no use, so obviously not the right approach.

What is the recommended way to work with files in the web root? Having to use sudo becomes an issue when wanting to work with files in there over SFTP, for example.

Thanks… Jonathan