These are the most common reasons a Bitcoin transaction looks “stuck”.

Bitcoin has a waiting line. People who pay higher fees usually get processed sooner. If your fee is low, you might wait longer.

Some wallets let you “bump the fee” by replacing the transaction with a higher-fee version.

If you control the coins being sent, you can sometimes create a second transaction that pays a higher fee, and miners include both.

If no explorer can see the transaction, your wallet/exchange may not have broadcast it yet, or it may have been replaced.