Can I buy a domain and change its content ?? should it has a negative influence in ranking in google??
no not at all it does not have any negative influence but you just need to look out and post from the relavant niche of the domain
if you bought a domain you can do what ever you like! and yes you can change the content if it`s on the same topic / keywords
if the activity domain it's something like vegetables-online.org and you plan to change content into something like computers and internet, then yes, it will affect the google rankings. Cheers!
If you have purchased the domain and want to change the content, then here two possibilities are there- 1>>>Suppose the existing content of your purchased domain is 'travel' and you need to edit the content by putting the another 'travel' content. Then in this case ranking will be fluctuated, depends upon how you have done such modification. 2>>Secondly suppose your purchased domain have initially 'travel' content and you need to update it with 'shopping' then i think you are using the domain for different purpose. In this case there is no such question of ranking drop arises because previously sites rank on the travel keyword and now the purpose is changed.