Its possible to add features Multisig on metamask on Ethereum & Avalanche network ?
It is not possible on Metamask but there are a few 3rd Party websites that allow you to do it
Ex : gnosis-safe . io
You can create a safe and then use that safe as your multisig wallet ( But using this safe is not easy, you will need some knowledge about blockchain and transacting through the blockchain (not just clicking few buttons but like actually coding in the transaction by using ABIs and more). Use this option only if know what you are doing. Wrong handling may result in loss of funds ).
Not financial advice and as always DYOR