Text operators
Use text operators to combine two or more text items into one larger item, indicate text constants in a formula, format the results of a formula, or represent special characters in a formula.
 
Appends the text string on the right to the end of the text string on the left. Text strings can be fields, constants enclosed in quotes, or certain functions.
Marks the beginning and the end of characters to be considered a text constant. Quotation marks without text between them indicate an empty value (no text). If you enter text into a formula without using quotation marks, FileMaker Pro tries to interpret the text as a field or function name.
Marks the beginning and the end of characters to be considered as text comments within a formula.
Related topics 
About formulas
Identifying text constants and special characters in formulas
Adding a new line to the results of a formula
Adding comments to a formula
Using a reserved word or symbol for a field or table name