Word document corrupts after converting to pdf and when trying to insert pdf pages

[chrissys30173948]

Every time I convert a word document to pdf and then insert other pdf pages the text on the word document corrupts ( letters are replaced with symbols) . When the word document is first exported or printed as pdf it is fine - only when extra pages are inserted does the corruption occur  - see example - what is cause and how can i resolve please? Begged work to get adobe because its the "best" then in first week this happens!!!