http://stackwallet.i2p/2023/04/28/coin-control-guide-for-stack-wallet.html
Step 2 Afterwards head back to the main My Stack screen and open the wallet that you’d like to use (hint: must be coin control compatible, i.e. BTC, BCH, LTC, DOGE, NMC, or PART). Looking to the menu along the bottom of your wallet screen, select the More option and then Coin Control from there.