Which is better: (it's part of the information on the tea box)
1. Tea facilitating digestion process
2. Tea which facilitates digestion process
3. A tea which facilitates a digestion process
SHOULD I USE THE ARTICLE "a" BEFORE DIGESTION PROCESS. I KNOW THAT BEFORE ABSTRACT NOUNS WE DON'T HAVE TO PUT ARTICLES AND THE WORD PROCESS,ACCORDING TO ME, IS AN ABSTRACT NOUN CAUSE WE CANNOT TOUCH IT.

Tea facilitates the digestive process. This says that all types of tea helps digestion.

A tea that facilitates the digestive process... This is only a noun phrase - there is no main verb. It distinguished some types of teas (those that help disgestion) from others, but doesn't say anything else, such as will help you sleep better or  control you appetite or whatever you want to say.

Abtract nouns can take articles: We could feel the anticipation in the auditorium building. or We improved the process.

Use "the digestive process." Which process? The digestive process. If you use "a digestive process" you are saying that there are many types, and this is just one of the types. Although a cow may have a different digestive process than a human, it's clear we're talking about humans, so use "the."