You place your cursor in the cell, and delete the formula.
You should not delete data that is crucial to the working of the spreadsheet. You should not delete data that will interfere with how formulas work.
It depends on what you want to delete. Deleting what is in cells can be done by selecting them and pressing the Delete key. You can also delete charts by selecting them and pressing the Delete key. To delete full rows and columns, you can select them and use the menu/ribbon options to remove them completely.
You can cut and paste it.
Click on the cell containing the formula and edit within the cell or in the cell bar at the top of the screen. You can do that by clicking in the formula or pressing the F2 key.
If you do not want to use a formula, you can delete the lower case letter (Del or Backspace) and type an upper case letter.
I am not sure what you mean by shared document. If you are talking about a document on SharePoint, ensure you have edit access and follow the procedures established on your SharePoint portal for deleting a document.
You can delete it if it has already been entered, by pressing the delete key. If you are still typing it in you can press the Esc key or the red X on the formula bar to stop it.
Same as deleting its content.
Use the delete key.
To number your rows in Excel, put a '1' in the first row, for instance in cell a1, the formula '=a1+1' in the second row, and then copy that formula to each additional row you want to number. Be careful, though, as inserting and deleting rows will mess the sequence up, and you will need to fix it as needed.
The delete key in Excel 2013 removes content, but not formatting.