The first tool for you to see this type of information is Google Search Console itself. You just need to enter your site registration, and in the left side menu click on “Links”.
This will show all the domains linked to your site that Google has already tracked.
Another free tool to find out how many backlinks your site has, is Ubersuggest , just enter your URL, and it will show your site’s backlinks.
Now let’s go to some paid SEO tools, the best one is Ahrefs . It has the function of Backlink Checker too, just enter the URL of your website, and it will show the backlinks that your website receives.
Another tool is SEMRush. In SEMRush you can also see how many backlinks your website has, it looks like ahrefs, you put your website URL and it will show the backlinks too.
It is important to note that all tools can contain different information, some will show more and others less, this is normal, there is no 100% perfect tool in this regard.
My personal recommendation is ahrefs and Google Search console, which contain the most up-to-date information.