When I use Rugcheck.xyz to check my token, it says that I did not lock liquidity and that this is dangerous.
Therefore, I want to lock liquidity for my token. How do I do this?
TL;DR: Burn the LP tokens you got from creating the pool for your token
When providing liquidity, you deposit your token as one side of a pair to a liquidity pool, usually with SOL or USDC as the other side of that pair. After providing this liquidity, you are given a number of LP tokens representing your position with which you can later on withdraw your token position. That is, unless you burn these LP tokens without withdrawing your LP position, at which point said position will be locked in, as the only way to withdraw it was using your LP tokens. This also explains why Rugcheck and other risk analyzers view this locking as a good sign, as it means you can't just pull liquidity at any time.
From Meteora:
"Please note that burning the LP token does not lock the liquidity in the pool. It will release your share of the pool to the other LPs. If you would like to permanently lock the liquidity in the pool, send the LP token to an invalid address instead."
I'm not sure what this invalid address would be though.