I have this married couple... they said they divorced in 2020. so asked me to file for them individually for single. However, they also need more time to provide me all the paperwork, so they need to file extensions.So I did, file single and extension for each of them.

Today, they contact me and want me to file joint return for them...I requested for the divorce document copies but haven't received them yet.

Just want to ask in advance, if they didn't finish the divorce process. Can I file them as joint after I file extension for them as single for each? if so how?

Thank you