For example I want to move from orderline CRM to Purchase or purchase to CRM, how we can achieve this,
How I can achieved through backend coding?

I have created menu Buyer "Incoming Buyer RFQ" and "Supplier RFQ" which are having 
actions: "sale.action_quotations_with_onboarding" and "purchase.purchase_rfq"respectively, 
now I will generate the Quotation in  "Incoming Buyer RFQ" and add product in here and
when I click confirm that new order should created in "Supplier RFQ". Please suggest I do such
functionality.

Please check the menu.xml which having actions from Sales and Purchase.

    id="menu_expora_erp_root"
              name="Expora ERP"
              sequence="0"/>
    id="menu_buyer_rfq_master"
              name="Buyer RFQ"
              parent="menu_expora_erp_root"
              sequence="0"/>
    id="menu_supplier_rfq_master"
              name="Supplier RFQ"
              parent="menu_expora_erp_root"
              sequence="1"/>

    id="menu_buyer_rfq"
              name="Incoming Buyer RFQ"
              action="sale.action_quotations_with_onboarding"
              parent="menu_buyer_rfq_master"
              sequence="0"/>

    id="menu_supplier_rfq"
              name="Supplier RFQ"
              action="purchase.purchase_rfq"
              parent="menu_supplier_rfq_master"
              sequence="0"/>