pass percentage in varchar in sql

if you mean you want to insert the string:

INSERT INTO MyTable (MyColumn) VALUES ('([phonenumber] like '%%')')

Then it's not the percent sign that causes the problem - it's the quote characters.

INSERT INTO MyTable (MyColumn) VALUES ('([phonenumber] like ''%%'')')

Will fix that.
If you means that you want phone numbers that start and end with a percent character then try:

SELECT * FROM MyTable WHERE phonenumber LIKE '[%]%[%]'

If that isn't what you want either, then we need much better information.

select * from MyTable where ohonenumber like '%' + @phonenumber + '%'