Hello Lee and hira,

Sikhi teaches Sikhs to respect human body, which contains His light (Jot Saroop). Any act of modification in form of tattoo or shaving, though not written in Guru Granth Sahib, but is a part of Sikh Rehit.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/hard-talk/2015-sikhism-and-tattoos.html

Regards, Arvind.