Deferring means applying for a course then taking a year out before going to university/college

If your thinking about taking a gap year, for what ever reason, before you start university/college, you can apply now and defer the start date by one year. You can do this by selecting a deferred start date in the ‘Choices’ section of the UCAS form. Universities/Colleges will often have their own guidance on applications for deferred entry; you should check their websites or prospectuses for details. Most universities/colleges will want students to explain their reason for deferring and their plans for the year out in their personal statement. Not all courses will accept deferred entry applications, so you should check the entry requirements carefully. Depending on your chosen course, it may be possible for you to defer after they have made their application, but you will need to contact the university to discuss this.

You can find more information on the UCAS website with regards to deferring your entry, and the process you go through 

If you didnt apply through UCAS for your course i.e. Part time Foundation Degree, HNC etc then contact the institution directly.