When a lead with notes and attachments in the related list is converted, does the files also saved in the account object? I haven't tried it yet. Thanks in advance.
Yes, the notes and attachments on the Lead will be linked to the converted Account and Contact.
Here's the salesforce reference
All notes and attachments from the lead are converted and attached to the new account and contact. All open activities and activity history from the lead are converted and attached to the new account, contact, and opportunity