If you don’t have access to Adobe-Acrobat and you want to highlight your text by online method, I can introduce you, two methods;
How to Highlight PDF Online;
1- Write in the address bar of your browser, “-www.pdfescape.com-”
2- Click on Free online;
3- Upload your pdf file;
4- Choose your desired file from your computer.
5- Click on the Annotate tab and click on “Highlight”.
6- Select the lines which you want to highlight them.
7- You can delete highlighted part, select them and click on recycle bin.
8- You can also change the colours of the highlighted part. Select them and choose your desired colour.
9- Click on save and download key.
10- you can open your file and save it and change the name.
How to Highlight PDF with Google Drive;
1- Write in the address bar of your browser, “-ww.drive.google.com-”
2- Click on “New”.
3- Upload your File.
4- Right-Click on your File, and Open your file with Google Docs.
5- Click on pen, you can specify your desired colour and by selecting lines and words you can highlight your file.
6- Convert your file to pdf Document;
7- Download your file and open it by Adobe-Acrobat;