As of today, Oct 12, 2020, there is no reprieve from late filing penalties for returns due Oct 15, 2020 and filed after that. This could change. Your client could possibly get penalty waived for reasonable cause.
Some suggest marking COVID-19 Relief at the top of the return or as statement.
Whether you can, and how to do this in ProConnect Tax, I don't know. I think it may have been discussed in the forum.
You've got good advice from Susan.
If you'd like to indicate "COVID-19" or whatever other texts on top of the return, click on General > Misc. Info./Direct Deposit on the left navigation panel, scroll down to the bottom of the input screen for the line Form 1040 text, and type in any text of your own choosing. Like we discussed in various other threads, nevertheless, it is unlikely the IRS will pay any attention to these texts and including it will unlikely offer your client any protection since there is no statutory, regulatory, or instructional requirement for doing so.
Still an AllStar
Sorry, I'm going to go off on a rant (nothing personal against you, it is just my annoyance at people who file extensions just to procrastinate) ...
The due date was July 15th. Has the person been hospitalized since July (or since February)? If not, they have had plenty of time to assemble their data for filing, and I don't see why they should be excused just because they procrastinated.