Text Properties Dialog Box, Alignment
Select Alignment on the Text Properties dialog box to position the values within a selected cell or data region. You can only format the horizontal alignment of individual text within a text box. If you would like to set padding values on the text box or how text is aligned vertically, use the corresponding text box properties.
Specify a value or type an expression that evaluates to the position where the text is positioned horizontally within a selected cell or data region. Click the Expression (fx) button to edit the expression.
General Display the text as calculated by Reporting Services. For more information about how text alignment is calculated, see Formatting Text and Placeholders (Report Builder 3.0 and SSRS).
Left Display the text as aligned to the left.
Center Display the text as aligned in the center.
Right Display the text as aligned to the right.