Transactions can get stuck for a number of reasons, but this most commonly comes down to using a transaction fee that was too low.
Since miners and validators generally prioritize transactions with the highest transaction fee (per byte), high fee transactions are usually processed quickly, while low fee ones can be left hanging for some time.
Depending on the web3 wallet you use, you will likely be able to find an option to increase the fee to make it more competitive or cancel the transaction entirely.
Please see MetaMask’s official documentation for a detailed guide.