Select id's from string - dynamic

Hello,

Can I select specific rows from a table using a string? The items in the string are sent into a stored procedure and can contain various id's and I do not how many.
For example here are Id=1 and Id=3

DECLARE @MyString varchar(500)='1,3'

It could also be Id=1, Id=3 and Id=4
DECLARE @MyString varchar(500)='1,3,4'

DECLARE @MyTable table(Id int,MyString varchar(50))
INSERT INTO @MyTable(Id,MyString)values(1,'One')
INSERT INTO @MyTable(Id,MyString)values(2,'Two')
INSERT INTO @MyTable(Id,MyString)values(3,'Three')
INSERT INTO @MyTable(Id,MyString)values(4,'Four')
INSERT INTO @MyTable(Id,MyString)values(5,'Five')