You create a wallet with two keys. One key is just like any other bitcoin key. You can use it to spend whenever you like.

The other key is timelocked and only works if you don't use your first key for some pre-specified length of time.

This is enforced by Bitcoin script on-chain, no third parties, no proprietary stuff. You can read more here: https://wizardsardine.com/blog/what-is-a-bitcoin-recovery-key/