E MAILS

i always let others to see my email inbox esp.. to someone that has no idea about what is it..
ill just gave my password and then they can access my yahoo account… here is my question…
is there any otherway where they cannot change my e-mail password?
and is there any otherway also to protect my message from deleting and asked first for a password…. and can i set a password to my folders email…
i just want to this for them to read only what is for them