Use an image viewer such as Windows Photos, Preview on Mac, or a third-party app
Open it with Adobe Photoshop, GIMP, or Paint.NET
Use Microsoft Paint on Windows
Use Preview on macOS
Use an online TIF viewer
Convert the TIF file to JPG, PNG, or PDF if needed
Right-click the file and choose Open With
Install a codec or plugin if your system cannot open it
Check whether the file is actually a TIFF file with a .tif or .tiff extension
Use a document scanner app if the file came from a scanner