There are mainly two ways to remove the formula in Excel and keep the text. No matter how many formulas you have used in your spreadsheet, you can delete or hide them without removing the values.

Here is a tutorial to lock or hide only the formula cells in an Excel workbook. You can also lock formulas in all worksheets in a workbook.

You may end up with an Excel sheet with lots of cells with a leading apostrophe, which tells Excel to interpret the cell content as a text. It may not be very pleasant and makes all the other formulas ...