What you've to know that there are many types of bitcoin ATM obviously.
Some bitcoin ATM machines support buy and sell bitcoin and there are some types that support only buy bitcoin (for your cash).
Here the list https://coinatmradar.com/manufacturers/
Genesis Coin (674 locations)
General Bytes (304 locations)
Lamassu (242 locations)
BitAccess (48 locations)
BitXatm (36 locations)
BTC facil (23 locations)
Covault (21 locations)
Skyhook (15 locations)
LocalBitcoins (12 locations)
zzBit (7 locations)
CoinOutlet (7 locations)
BitTeller (6 locations)
And, pay attention to bitcoin ATM fees and confirmation time as it will be different on each type of machine and depend on blockchain network.