To insert a clickable checkbox in Word, first show the Developer tab: go to File > Options > Customize Ribbon, tick Developer and click OK. Then place your cursor where the checkbox should go and click Developer > Check Box Content Control in the Controls group. Click the box to tick or untick it. For a checklist that will be printed and ticked by hand, use Home > Bullets > Define New Bullet > Symbol and choose an empty box symbol instead.
To remove duplicates in Excel, click anywhere in your data, go to the Data tab and click Remove Duplicates in the Data Tools group. Tick the columns Excel should compare (all columns removes only identical rows; one column removes repeats of that value), make sure My data has headers is ticked, and click OK. Excel deletes the duplicate rows, keeps the first occurrence of each, and tells you how many were removed.
To lock cells in Excel, select the whole sheet, press Ctrl + 1, and on the Protection tab untick Locked. Then select only the cells you want to lock, press Ctrl + 1 again and tick Locked. Finally, go to Review > Protect Sheet, choose what users can still do, add a password if you want one, and click OK. Locked cells can no longer be edited until you go to Review > Unprotect Sheet.
To add page numbers in Word, go to the Insert tab, click Page Number in the Header & Footer group, choose a position (Top of Page, Bottom of Page or Page Margins) and click a style. Word numbers every page automatically and updates the numbers as you add or remove pages. To leave the first page unnumbered, tick Different First Page on the Header & Footer tab. To change the style (such as i, ii, iii) or the starting number, use Page Number > Format Page Numbers.
To freeze panes in Excel, go to the View tab and click Freeze Panes in the Window group. Choose Freeze Top Row to keep your headings visible, or Freeze First Column to keep the left column visible. To freeze several rows and columns at once, select the cell immediately below and to the right of the rows and columns you want to lock (for example C3 to lock rows 1 to 2 and columns A to B), then choose Freeze Panes. To undo it, click Freeze Panes > Unfreeze Panes.