Copy and paste string to Excel (android app)
If you are not typing a formula, then you should not use = as the first character in Excel. If you are typing a formula, then make sure that you have typed it correctly. As stated here:

The #NAME? error signifies that something needs to be corrected in the syntax, so when you see the error in your formula, resolve it. Do not use any error-handling functions such as IFERROR to mask the error

To solve your issue, type a single quote ' before =, or replace the equal sign with a single quote. Excel will recognizes that you are not typing a formula and will show the value you entered.