In Order to implement Line Break in SSRS, there are 2 ways
<br/>
tag to introduce line break within the expression ="first line of text. Param1 value: " & Parameters!Param1.Value & "<br/>" & Parameters!Param1.Value
="first line of text. Param1 value: " & Parameters!Param1.Value & Environment.NewLine()
& Parameters!Param1.Value
Note:- Always remember to leave a space after every "&" (ampersand) in order to evaluate the expression properly