I'm new to WordPress. I have lot of issues through spam comments, it gets more time to check and delete those manually. I want to keep the comment fields. So is there any way to block/track spam comments in comment fields?
Just install a good anti-spam plugin. They will monitors site's comments for spam and automatically blocks spam comments.
BTW WordPress come with Akismet which is a spam protection plugin installed by default. To enable the plugin, go to the Plugins and activate the Plugin.
I'd actually recommend that you disable comments for now. I know that as a new user, you are thrilled to get a response but my experience shows that quality comments only come after you have established yourself. In the beginning of your career as a blogger or website owner, it is ususally just tons of spam you get.
If you really want to keep the comment fields, yes, install an anti-spam plugin and try to blacklist words and URLs in comments (Settings->Discussion->Comment moderation/Comment blacklist.
Keep though in mind that spammers don't have anything else to do but figure out smart ways to spam you, so my best advice would be to continue moderating manually and double checking for hidden links in author names and all other field of a comment.
Anti-spam plugins sometimes are ok, but sometimes users do not want to overload their website with plugins because plugins makes website slower.
So, in case you're unhappy with your anti-spam plugin, I recommend you to try a method with creating a hidden field in the comment form – it completely prevents automatic spam (actually it is 99% of all spam comments).
Here is the step by step guide how to implement it https://rudrastyh.com/wordpress/spam-protection-no-plugins.html