When working with your word document, you may need to add PDF as an attachment and you can open these PDF files when you click on them. Please note that adding a file as an attachment is different from merging the two files together.
The easy way is to right-click on the PDF file, and select copy in the dialog box, then paste to the word file.
Alternatively, please follow the steps to insert the PDF into the word file:
Step 1: Click the "Insert" tab from the ribbon;
Step 2: Click the "Object" command from the "Text" area;
Step 3: In the "Object" window, browse to the file from the location;
Step 4: Click "OK" and the PDF will display in the Word file as an object.