Would it be wrong if I take charges for writing and managing some pages in wikipedia?

It's not forbidden, but it is discouraged, because when you are paid to write something, you are by definition not neutral about it. If you happen to write things that strictly adhere to Wikipedia's policies of https://en.wikipedia.org/wiki/WP:V and https://en.wikipedia.org/wiki/WP:NPOV, then it's probably fine, but it is extremely hard. More information can be found at the page https://en.wikipedia.org/wiki/Wikipedia:PAY#Paid_editing. Note that the above pertains to the English Wikipedia, but Wikipedias in other languages have comparable policies.

Quoting to wikipedia itslef, this is what wikipedia says about "Paid Editing". I somewhat found my answer, I guess. Paid editing https://en.wikipedia.org/wiki/Wikipedia:PAY#Paid_editing Paid editing is the practice of accepting money to edit Wikipedia. Paid advocacy, that is, being paid to promote something or someone on Wikipedia, is a subset of paid editing. If you intend to participate in paid editing, transparency and neutrality are key. Editing in a way that biases the coverage of Wikipedia or that violates our core policies is not acceptable. The act of accepting money or rewards for editing Wikipedia is not always problematic. There may be benign examples of editors being paid – for example, a university asking you to write up its https://en.wiktionary.org/wiki/warts_and_all history. The https://en.wikipedia.org/wiki/Wikipedia:REWARD, a place where editors can post incentives, financial or otherwise, is another benign example. This is a transparent process, and the goal is usually to raise articles to featured or good article status. But be wary of editors there asking you to make edits that challenge your sense of neutrality. By this, the focus seems to be on Notability and Neutral presentation. There isn't any objection if someone accepts grants against expanding the wikipedia contents. :)