Can I restore my contacts using CSV file?
Not exactly. Restoring contacts using VCF (vCard) file is standard feature of iOS platform. But Mail app can't restore contacts from a CSV file.
So you must first convert CSV file to a VCF file on your computer and then send it to your email account to open with Mail app on your device.
So you must first convert CSV file to a VCF file on your computer and then send it to your email account to open with Mail app on your device.