Unlike a word processing file, the text you see on a PDF is permanently embedded onto each page which means it can no longer be edited unless the text is in an active form field that hasn't been "flattened", but you can still use DocHub to cover up any existing text using the Whiteout Tool and then add new text on top of it by selecting the Text Tool on the Tool Bar and clicking on the whited out area to add new text.
You can also add any other annotations over the whited out area:
Adding Whiteout to areas of a PDF
Another option is to use Insert Image or Stamp Tool annotations to cover up any text.
The Difference Between Embedded Text and an Image of Text on a PDF
When it comes to text on PDF documents, there are two kinds:
- embedded text
- image of text (i.e. from a scanner).
If you are unable to select or highlight text with your mouse cursor then it is definitely a scanned image of text on paper instead of a regular PDF with embedded, digital text. If you were the one who scanned the document and still have the original paper(s), there are some scanners that offer OCR (optical character recognition) technology which will attempt decipher any text on paper and then embed the text into a PDF.
If you did upload a file that has just an image with text, I would recommend downloading it from DocHub by clicking Download / Export > Computer > Download and then use a free online OCR app to try to create a PDF with embedded text. Just search the web for "free online OCR app", and there will be several free ones. Be sure to choose one that offers PDF output such as http://www.free-online-ocr.com.
Since some digital scans have better resolution and readability than others, using OCR on your document may or may not convert all of the scanned text into the most accurate embedded text depending on several factors such as how legible the text is in the original, the style of font, and the DPI (resolution) of the scan, so if the text is not detected and converted correctly after using the first free OCR online app, you should try using another one to see if it has better results.
Once you have a PDF file where the text is actually embedded and selectable and no longer an image, you can then simply re-upload the document to DocHub.