Hi Amit -
To get you started, here's some info:
1. Yes, you can absolutely use the MethodAPI to import leads.
2. We have some documentation and general sample code here: https://www.method.me/api/
3. There may not be an exact example of importing a lead, but here's some start info:
a) Use MethodAPIFieldListV2 to get a full lead of fields from the "Customer" table.
b) You can use MethodAPIInsertV2 to insert into the "Customer" table. But the key to inserting a Lead is to include the IsLeadStatusOnly field in your insert list, and set that value to true. This way they get imported as a lead rather than a customer.