After your trade deadline passes, you can longer propose or accept trades.
For example, if your deadline is Week 10 like the image above, once your first waiver period clears following the conclusion of Week 10 games, no more trades can be accepted.
That means if you are using Custom Daily Waivers or After Games Waivers Clear, you can trade until those waivers clear.
If you are not using any of those waiver options, your trade deadline will be shortly after the conclusion of the Monday Night Football game.
It is possible for trades to be accepted prior to your trade deadline, and then processed afterward. That can happen if you have a review period is enabled:
When can our league trade again?
For dynasty and keeper leagues, trading will reopen as soon as your league's playoff has ended.
We require leagues to be renewed or transitioned each season, and we recommend that you do that first before conducting trades.
Otherwise, any moves you make after your league's championship will not carry over to the new version of the league.