Can communications via email (ex: deposit return letter, or sending invoices) be considered formal and written communication? 

Communication with the Current Property Management Company•First, establish open communication with the outgoing PMC to coordinate the transfer of information and documents.

3) When it comes to communication with tenants, especially around lease renewals, I’ve noticed some gaps in the tools I’m familiar with.

Communication - now, if the guest is ready to book but has a question or two about the home, swift, friendly and informative communication is essential.

Lender Flexibility: Every lender has different rules, so it's important to communicate your intended use of the property upfront.

These guys can be larger and clunky when it comes to appraisal turn times as well as overall communication.  

As soon as she started to fall behind/be late more than once, I'd not renew her lease especially if tenants aren't communicating with you.If there is extensive mold, tell her to remove her items so you can treat the property. 

The KEY AT THIS POINT IS ESTABLISHING COMMUNICATION with the tenant because a great option could be cash for keys as @Sean McKee mentioned, but you can't do that without having a conversation.During these challenging times I try to remind myself that the tenant is obviously going through some seriously challenging times and no matter what landlord problems are still "good problems" to have...

Quote from @Jamie Banks: After receiving the request on Furnished Finder I reached out to the guest via their preferred communication method.

When your tenant communicates with you, at least acknowledge their communication so they know they've been heard.