Keyword analysis and re-writing website content to rank higher

Hello!
For my charity The 88 Project I'm looking to improve our website content so it's easier for our audience to find us online. We are advocating for free speech in Vietnam, so free speech, human rights, and Vietnam are important terms for us. I am looking for help from a specialist who can do a keyword analysis for us - looking at our objectives but also at what's already out there - so they can advise on keywords for us to focus on. On the basis of that research, I would like you to then help to re-write the current website content and meta-descriptions etc. to improve the ranking based on those keywords/terms.