I didn't know my address document is required for verifying the account. Should I give the document to them? Is it safe?

https://www.greasewallet.com/     

We strongly suggest you immediately stop giving away your personal information. Grease Wallet is a fraudulent platform and the Financial Conduct Authority (FCA) has warned the public of this illegal firm.

Grease Wallet claims to be operated by Grease Wallet Inc. registered with the Companies House (CH) under company number 02789650. However, we searched the CH's website for this number and found it belongs to another company. This means Grease Wallet is using details of the other genuine firm to appear legitimate. 

Furthermore, the FCA, the UK financial regulator, has issued a warning against Grease Wallet, announcing its illegitimacy in the financial industry.

In essence, Grease Wallet is an unlicensed broker coming with significant risks, such as fraud and identity theft. Without regulatory oversight, investors dealing with this platform are not protected. Therefore, we advise investors against trading with unlicensed brokers like Grease Wallet and instead to choose a fully regulated one.