CONTAINSSTRING Returns TRUE or FALSE indicating whether one string contains another string.
Syntax
CONTAINSSTRING(within_text, find_text)
Parameters
within_text – The text in which you want to search for find_text.
find_text – The text you want to find.
Return Value
TRUE if find_text is a substring of within_text; otherwise FALSE.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference