Yes, It does. Ensure you are linking to a high authority site and a non-spammy link.
Note: Moderator disabled links as too spammy.
Yes, if done properly. As long as the websites are not spammy, it won't affect your ranking, rather it will strengthen your page authority which in turn boost your ranking.
Tips to use when adding an external link
1. Make sure the site has a higher Domain Authority (DA) than your site.
2. Avoid spammy sites, it will affect your SEO.
3. Link to sites that are in your niche (related sites only), e.g If you run a pet shop, only link to sites that are into pet business.
I hope I have been of help.
Website: 2oddsblog.wordpress.com/ (Moderator disabled link.)