Excel’s UPPER function has your back. Syntax: =UPPER (text) This function takes one argument—the text you want to convert. You can reference a cell or input the text directly into the formula.

An option in Excel allows users to import all the texts into the spreadsheet (convert text file into Excel ) so that users can do the job quickly.

If the DAT file you're trying to open is text, you can convert the file into text in the Microsoft Excel program by first saving it as a CSV file.