How can i access col name from parameter?

CREATE PROCEDURE [dbo].[r_CreateCol]

@col nvarchar(100)
AS
ALTER TABLE Summary
ADD @col  nvarchar(100);
GO

 In this case, you'd need dynamic sql

CREATE PROCEDURE [dbo].[r_CreateCol]

@col nvarchar(255)
AS

declare @sql nvarchar(1000)
select @sql = 'ALTER TABLE dbo.Summary ADD ' + @col + ' nvarchar(100)'

exec sp_executesql @sql

GO
 
exec r_CreateCol 'newcol'
go

sp_help Summary
go
 

What are you benifitting from this proc...