The first step is to go to the corrector place and ask the correct
question. This is an English language forum. Questions are best asked in
standard English. That which you pose has misspelled tactile and contains
a grammatical subject-verb agreement error at the least and is nonsense
at the worst. People do not tend to respond well to lazy, careless
effort.
Did you mean:
What is the function of tactile receptors in invertebrates?
(What do they do?)
or
Describe the functioning of a tactile receptor in invertebrates.
(How do they do it?)
or something else entirely?
OK. Now that I have gotten the pedantic out of the way, we are still not
on firm ground. This is not a homework centre. Try a Google or other
search to begin. Look for a general source to start and go to more
specialized sources as your understanding increases.
If you are going to spend the time on it, you might as well do a good job
and learn something worthwhile.
Good luck.