I use latex a lot for academic purposes (usually sharelatex and more recently, overleaf v2), because of that I always need some math or physics related packages like amsmath, siunitix and a lot of other ones. Because of that, it would be very practical for me if it was possible to configure my account in a way that everytime I create a new blank project those packages were already included, is there any way to do that?
I would suggest creating a single project that contains all the customisations you're after, including extra fonts, custom document classes and/or packages and possibly often-used images. Let's call this project
You can add whatever detail you want with comments and other bells and whistles. Then you can copy the project whenever you want to work on a new article:
Once you've created a copy, rename it and work on it.
This approach is slightly different from a template. The latter you'll have to maintain on GitHub or upload every time you want to use it, as this is the only option on using it in OverLeaf: