im getting a grey background box inside a cell with text how do i remove it

This appears to be on an iPad.

Once the text is selected

1. tap on the paintbrush in the toolbar
2. select the Cell section
3. tap on the three dots in the sub-section for text effect (Bold/italic, etc.)
4. 
5. scroll up until you see Text Background at the bottom
6. tap on the color swatch
7. scroll up in Preset and choose No Fill

It would be helpful to post a picture of what you see.

Press Shift-Command-5, frame a meaningful area, look in the options where the picture file will be saved (desktop by default), and press Enter. Add to the discussion with the second-last icon (mountain and moon) at the bottom of this text field.