Hi @Sunil_Bhatnagar, it's not a wise move to kickstart your Blogging journey without a 'custom domain' name, you can easily get a new one (preferably .com for less than Rs.100) and configure it with your blog.
That way it looks professional and spam-free. You said 'particular keyword' right? Is it a trending keyword or an evergreen one? As in, apps like Prisma, Pokémon GO, etc. were 'trending' once... but now, not much... whereas Evergreen ones are like topics which stay longer, like VR (Virtual Reality).