that particular screenshot is from the trade machine at https://fanspo.com/nba/trade-machine. The green numbers are player options. blue is team options.

But normally I just google “[team] payroll” and the first hit is usually basketball reference which is quicker, but does not have the trading feature.

https://www.basketball-reference.com/contracts/MIA.html

spotrac is another reference that is extremely thorough, but way more data to sift through.

https://www.spotrac.com/nba/miami-heat/cap/