Howdy! I recently decided I wanted to jump back into Defold and a lot has changed since I last used this engine. I was looking to give a friend of my access to my game so we can both work on it simultaneously.
Last time I used Defold you could do this by adding people in the online dashboard, is this still a thing? Can you still work as a team? If so, how do you go about doing this now?
Thank you for your time 
The dashboard was removed quite a while ago, so you just need to upload your project to a new host (Github and Bitbucket are both pretty good, and free).
I think you will still have a “.git” folder (hidden) in your project folder. If so, you will still have all your past history and just need to reset the origin address for it. If not, it’s no big deal, you just won’t have your work history.
If that all sounds like gibberish, what you want is called “version control”, or “source control”. You can look up tutorials on “how to use git”. Git is one of the most common (I think?) version control systems. Your team members will need to install git on your computers if you don’t have it already. You can use it from the command line, or there are a whole bunch graphical programs to use (look up “git clients”). Once you’ve decided on a place to host it, you’ll just need to give access to your friend’s account through the site.
Nothing has really changed, just the hosting service was discontinued, you can still “synchronize” through the editor if you want. There’s actually a manual about this: https://defold.com/manuals/version-control/
Like @ross.grams says you could use GitHub or Bitbucket (or any other Git host even your own server). Bitbucket is great and has been free for private repos for a long time. But GitHub is also now free for private repos too. I prefer to never sync with the builtin editor features but to always do it with external clients like GitHub Desktop or Sourcetree. It is still useful to see the files changed in the editor.