Click protection tool

Click to mark ciphertext.

Select the text to hide.

Click Apply Ciphertext.

At this point, the text that needs to be hidden is completely hidden.

then

It's a chart that needs to be kept secret.

Here is the protection function.

Just mark the ciphertext

From selected text to boxed chart.

Here you can choose the size and location of the box at will.

Then click also apply ciphertext?