After user registration sending mail subject wordpress

Wordpress after registration,I got one mail with username,password,login link,And the mail is coming from from: WordPress

wordpress@mywebsitename.com ,

why and how can I change It to mywebsite like that Can you help me(I dont want wordpress name to display to client or customers)...

And I got the link like that Password: mI11kzfmySDb

http://ift.tt/YD36Oc

How can I change Thins link to

http://ift.tt/1IOvEFR