Letters of recommendation are useful, even necessary, to apply for graduate program as well as for other purposes.
Contact your advisor and provide him/her with the necessary documentation. A recommendation letter is issued for exemplary students only. Your faculty advisor must review your file and the documentation that you provide, as well as consult with other faculty members, in order to determine whether it is possible to issue the letter. Allow a minimum of 4 weeks for the whole process to be completed.