Expiring Contracts

First time doing this league/site ..

Regarding players who have expiring contracts. Is there a period after the season but before free agency to sign your players before they are released to free agency? Or am I better served to just sign them before the season ends?

You're better served to sign them before the season ends - they will still be visible on your roster before the draft, but once the season rolls over any team is able to sign them.