You can not directly check your bitcoin paper wallet balance because your wallet is not online and it is offline on a printed piece of paper. To check your btc paper wallet balance, you need a blockchain explorer service. A blockchain explorer is basically a blockchain search engine, that contains all the cryptocurrency information stored in it. You can search for a specific piece of information that is present on the blockchain.
Your search activity on crypto blockchains is known as a transaction.
There are many types of blockchain explorers, some are specialists in one crypto while some are specialists in many cryptocurrencies.
Here we will take examples of those blockchain search engines, which are particularly for bitcoin and we will see how to check btc paper wallet balance by using a blockchain explorer.
→ Select your blockchain explorer. In the case of btc, choose Btc.com or Blockchain.com explorer
→ After selecting one blockchain explorer, write a public key into it and the blockchain explorer would retrieve your paper wallet transaction history or balance for you.