I am using overleaf to make excercises with my group in our different classes.
We have multiple projects, one for each subject, all with the same preamble. We of course update the preamble from time to time to accommodate for the new commands and functionalties we need. This is very cumbersome given that I have to then also jump into each other project I have to update the preamble in there. Is there a way to call one master preamble in all of ones projects?
To be able to have a common preamble for you overleaf documents you can start with this guide to share files from project to project.
Then create a file, say, preamble.tex with your common packages and definitions and load it in all the projects you want.
Any new definition or change can be done in preamble.tex and loaded in other documents by just refreshing that file.
(Feel free to edit this answer to made it complete and understandable)