The most common way to view the code of a stored procedure in SSMS is doing a right-click on the stored procedure and select Script Stored Procedure as and select CREATE To.
But this is not practical when you have several stored procedures to look at.
Another way to do it by using a script:
USE [DATABASENAME] GO EXEC sp_helptext STOREDPROCEDURENAME GO
You might want to set the Results to Text for easy copy and paste for further editing.
Further Reading
How to view the stored procedure code in SQL Server Management Studio
How to Find a String in SQL Server Stored Procedures
How to Find All References to an Object in a SQL Server Database
How to Get Table Definition in SQL Server
