I am bidding regularly as a Flutter android & iOS developer but my conversion rate is very poor. I am getting very few responses for interviews. I include in the cover letter my intro, and my skill set according to the job description, working process, portfolio, and so on. Besides, the cover letter, I am sending some of my project codes in zip format. Here you go with my cover letter from the given attachment.
Thanks in advance.
Your proposal is about 20 times longer than necessary. Most clients will look at it and think, "I'm not going to read all of that!" Most of that information belongs in your profile, not your proposal.
A client can only see the first two lines of your proposal and then must click to open it and see the rest. If you don't address the client's specific needs in those first two lines, you've lost them.