Here are some common transaction codes (t-codes) used in the Procure-to-Pay (PTP) process in SAP:
ME21N - Create Purchase Order
ME22N - Change Purchase Order
ME23N - Display Purchase Order
ME29N - Cancel Purchase Order
ME51N - Create Purchase Requisition
ME52N - Change Purchase Requisition
ME53N - Display Purchase Requisition
ME59N - Automatic Generation of Purchase Orders
MIGO - Goods Receipt for Purchase Order
MIRO - Invoice Receipt
MR8M - Cancel Invoice Document
F110 - Automatic Payment Run
FBL1N - Vendor Line Item Display
FBL3N - G/L Account Line Item Display
F.80 - Vendor Balances in Local Currency
Please note that the t-codes used may vary depending on the specific requirements and configurations of your organization.