How much time it will take to index 500k+ data from Mongodb to typesense

Depends on number of fields indexed but if you do batched import should be < 2 minutes.

if i have indexed 10k data and want to update it with next 10k data so client.collections('companies').documents('124').update(document) how can i update it from here

Refer to the earlier documents by their id field. Use the same id to update them.

my doubt is i have 20k data, once i index 10k after some time i want rest data to be indexed so is there any way to update previous index data

Have you looked into the import API?

okay