It is strongly recommended that you do not give your account login information to anybody. It is a very risky thing to do. They may delete your items or characters, or do things to get your account banned and there is no undoing those actions. If you're unsure what kind of activity may lead to a ban, please read the section about Account Recoveries in [url=https://help.bungie.net/hc/en-us/articles/360049517431-Destiny-Account-Restrictions-and-Banning-Policies]this article[/url]. Allowing someone to use your account to farm endgame activities for rewards is very likely bannable.