LEFT Returns the specified number of characters from the start of a text string.
Syntax
LEFT(text, num_chars)
Parameters
text – The text string containing the characters you want to extract, or a reference to a column that contains text.
num_chars – (optional) The number of characters you want LEFT to extract; if omitted, 1.
Return Value
A text string.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference