I want to expand my English vocabulary and also need some tips on how to remember words

Tips for how to remember words

I don't to join any institute, so is there anyway I can learn english online

For example, being able to express complex ideas in an unambiguous manner

Hang around English speakers, and keep practicing or go here,

https://www.rosettastone.com/

There are many ways of introducing context into your vocabulary learning, the simplest being to learn vocabulary in sentences. This has additional benefits of introducing you to several words at a time, and clarifying their meaning, which may not always be obvious from a simple dictionary translation.

Beyond sentences, you can experiment with learning words with stories, songs or just everyday situations. For example, rather than learning weather related words on their own, look up a weather forecast online, and try to imagine a conversation about weather next week, and how it’ll affect the fishing trip you’ve been looking forward to so much.

Kids shows can help, and I'm not being facetious, I'm totally serious. They teach things slowly, in a way that's easy to understand. Sesame Street, and shows like that, are great for someone just learning English. Then, once you're comfortable with that level you move on to more complex shows or books.

I'm sure there are a lot of things you can find on YouTube that will also help.

Go to the public library that "belongs" to you and get a library card. Look at children's picture books; check out a few. Go home and read them out loud. Read them to someone who speaks good English and will correct your pronunciation. Look up words you don't know. Notice the phrasing of each sentence. Does each picture help you read and understand better? It might be helpful for you to rewrite those same sentences yourself on a piece of lined paper, so you can review them later. For each sentence, figure out the subject, verb (action word[(s]), direct object, prepositional phrases. (If you don't know what these are, check out from the library a very basic grammar book or find a good basic grammar site online.) Also, ask a librarian if they or a nearby library or another organization offers conversational English for non-native-English speakers. Join such a group.