Highlight PDF substring that goes onto new line

Using the Aspose.PDF library, I am able to highlight full words using regex and I can highlight substrings. But what is the code I should use if the substring continues onto a different line?

https://www.entnet.org/wp-content/uploads/2021/04/Instructions-for-Adding-Your-Logo-2.pdf

Using the above as an example. On the first page in the second column is the substring ‘how to save your logo’ that extends to two lines. I want to programmatically search and highlight that substring. How would I go about this?

@echeung

Please note that we use ‘\r\n’ as newline in the extracted text. Therefore we recommend ‘(?i)firstline\r\nsecondline\b’ expression to find words separated by newline marker. Or ‘(?i)firstline\s+secondline\b’ expression to find both plain and multi-line positioning of desired text. Hope this helps you.