1. Neither are checked.

The preview example shows the result.
If the find phrase was 'cat', then without 'whole words only' checked, it will even find it in parts of words.
Also, without 'Match case' checked, it will match both upper and lower case letters.

2. 'Find whole words only' checked.

Now if the find phrase is a smaller part of a bigger word, it is ignored.

3. Match case of 'find' phrase checked.

Now the find phrase only matches when the case also matches.
So the find phrase 'cat' will not match 'Cat'.

*NOTE: 'Match case' ONLY looks at the FIRST letter found.

4. Both checked.

If both options are checked, then only whole words beginning with the same case as the find phrase will be found.

This option causes all text items found in the document to be selected. 

No highlighting is applied to the found text in this case, as it will already be coloured light blue when it is selected.

NOTE: After the found text is selected, further find / replace commands will only apply to the selected text. Simply click anywhere on the document to remove the selection.

1. Adapt case of 'replace' phrase to target is NOT checked.

Then the 'replace' phrase simply replaces the found text unchanged.
(In the example, the word 'Dog', starting with a capital 'D', replaces both the word 'cat' and the word 'Cat'.)

2. Adapt case of 'replace' phrase to target checked.

Then the case of the first letter of the 'replace' phrase is changed to match the word it is replacing. This is very useful when some of the words replaced are at the beginning of a sentence.
(In the example, the word 'Dog' is changed to 'dog' when it replaces 'cat'. )