I want to target multiple keywords with same piece of content (I am thinking to add multiple keywords separated by commas in title and description of the page). So, is it the right approach or I am making any mistake?
by using multiple related keywords in the title and description separated by commas, you'll actually be creating a bad overall user experience for your readers and users.
I'd suggest not using multiple keywords (even if they are related) in your title and meta description. Instead, only focus on using your main target keyword once or twice.
I've always used a pipe character (|) to separate my keyword strings, but Google also recognizes commas. I use a similar approach to my SEO; I include keyword phrases that are supported by the content and try to limit it to no more than 3 very closely related terms. Example here: https://driltech.net/mud-motor-drilling.php
If I have trouble narrowing it down I look at the possibility I need to refine my keywords or I need to move some of the content to a page of its own. Each page is your elevator pitch, it should be focused and precise(ish). This is always an issue when I am trying to optimize overview-type pages because it covers a broad swath of content and you know you can't win on every term.
I found this article about writing title tags and meta descriptions, it is from 2015 but everything pretty much still rings true.