Allow a Text Box to Grow or Shrink (Report Builder and SSRS)
By default, text boxes are a fixed size. You can set options that let the text box expand or shrink based on its contents. These options correspond to the CanGrow or CanShrink properties in the Properties pane.
You can create and modify report definitions (.rdl) in Report Builder and in Report Designer in SQL Server Data Tools. Each authoring environment provides different ways to create, open, and save reports and related items. For more information, see Designing Reports in Report Designer and Report Builder (SSRS) on the Web at microsoft.com.
To Allow a Text Box to Grow or Shrink
Right-click the text box and click Text Box Properties.
Click the General tab.
To allow the text box to expand vertically based on its contents, select Allow height to increase.
To allow the text box to shrink based on its contents, select Allow height to decrease.