It's case-sensitive. Luckily, the address contains a checksum, so the wallet will tell you the address is invalid when you make a mistake. And to avoid confusion, the characters 0,O, I and l are not used.
On the other hand, Ethereum addresses didn't contain a checksum from the start and were case-insensitive. This has led to some expensive mistakes. Today, you can convert a case-insensitive ETH address to a case-sensitive address with a checksum, which otherwise consists of the same letters.
Anyway, I'd recommend copying the address or scanning a QR code on your phone. Do check that you copied the address correctly. There is malware that changes the address in your clipboard in order to steal your bitcoin.
It is case sensitive! If you try to send bitcoin and if you mistakenly enter letter with wrong case, wallet shouldn't send the amount and you'll receive an invalid address error.