custom format for numbers

Available number format codes and instructions for building custom number formats (I found this one of my most referred to help files while learning Excel):
https://support.office.com/en-us/art...3-80F18B4EAE68

It's not clear to me exactly what you are trying to do. To get the text string "+ and -" in front of numbers formatted as per cent, enclose the text in quotation marks along with the usual per cent number format. Something like "+ and -"0.00%.

Maybe

Custom Format

• Right click cell (or Ctrl + 1)
• Format Cells
• Number
• Custom
• Type: +0%;-0%;;

Number Formats