The Format > Hyperlink style let you treat the cell contents as a hyperlink that is activated after a single mouse click or pressing the SPACE key. To edit it, double click it or use the ENTER/F2 keys (unless you re-define the ENTER in the global or AutoScroll options).
The link can be any location in the current workbook, other workbook files, www addresses, e-mail address,
files on a local disc etc.
You can explicitly specify the link type/protocol adding one of the following prefixes:
Note: Clicking a given workbook hyperlink causes jumping to the specified location. If this is within the same workbook and you later want to go back to the original location from before that jump, click the "back" bookmark toolbar button (Alt+F11). (This jump-back option remains valid till you use any bookmarks commands for other purposes.)
The easiest way to create a hyperlink to the current cell is to use one of the Edit > Copy as Hyperlink commands. To paste/insert such copied and already formatted hyperlink in the same or in other workbooks you just need to use the plain Paste command. The Ctrl+H shortcut is automatically re-assigned to the most recent "hyperlink" command variant.