When you receive Bitcoin (or several other coins), your balance isn't one big pool — it's a collection of individual "outputs," like separate bills in a wallet. Coin control lets you see those outputs and choose which ones a transaction spends. That matters for privacy: it keeps coins you'd rather not link together — say, a KYC exchange withdrawal and a private payment — from being spent in the same transaction.
Coin control is available for Bitcoin, Litecoin, Bitcoin Cash, Dogecoin, Monero, and Decred wallets.
You don't have to freeze coins to control one payment: the Send and Swap screens also let you filter which outputs that one transaction may use, without changing anything permanently. Look for Coin Control under the Send screen's Advanced Settings.
If your available balance looks lower than expected, check here first — frozen outputs are excluded from what you can spend. See Why is my Available Balance 0? for other causes.

