The meaning of T1 in option trading

I once had a $19,000 sitting on my account that I wanted to cash out after trading that same day; and the withdraw button was greyed out. Because it said that my settled cash was $0. I reached out to a rep at Webull and this is what she responded with:

I had no idea what, “Option trades settle on T+1” meant at the time.

Here’s what this odd letter + number means.

The meaning of “T+1”

The letter “T” stands for trade date and the number stands for days. So for example:

Let’s say you make an option trade for $AAPL (Apple) 170 calls on Jan 28th 2022.

and sell it the same day. The day your sell option contracts is “T” and add 1 more day and that’s when your money will be available.

If you bought $AAPL on Jan 28th, and sold the same day. Your money will be ready Jan 29th.

settle funds length = trade date (sell date) + 1 day

That’s it!