@rezamo It doesn't matter where you are. YC funds people from anywhere. It helps to speak decent English, but I've met YC company founders who weren't great English speakers.
Build a good demo, if you can. Focus on the core of the thing, not the flash around it. You don't need fancy onboarding, SEO, whatever, for a demo. You need to prove you can build the product you say you're building.
Build a good team. Prove you have the right expertise to solve the problem you're setting out to solve. This doesn't have to be formal education, but some sort of real world interaction with the problem is extremely valuable. The more specialized the industry you're working in, the more important this is. Consumer apps may not need any special knowledge, but robotics, or AI, or manufacturing, or logistics, or medicine, almost certainly do.
Be extremely clear about what you're doing, don't get lost in the weeds when you describe it on the application or in the interview if you get to that stage.
Practice describing your idea (the "elevator pitch") to friends/family/strangers/etc. Someone with no expert knowledge in your field should be able to describe your idea pretty accurately after they get the elevator pitch. If they don't/can't, you've failed and need to simplify or polish the pitch. You don't get a lot of time or attention when applying for Y Combinator, because there are literally thousands of applicants every batch. They have a lot of reviewers, so your application will get seen by several people, but every application is only looked at for a few minutes by each reviewer, at best (and applications that are confusing or vague are ruled out more quickly, since that's a strong signal that the company isn't ready for YC yet).
I really can't stress this enough: If you can't describe your idea
clearly in a few words, you almost certainly can't get into YC. You need that pitch for every subsequent stage, so if you can't make the pitch well, you aren't done with the pre-funding work yet. The pitch is how you'll get your first customers, it's how you'll raise further funding, it's how you'll make partnerships, it's how you'll garner interest for an acquisition or an IPO.
One of the biggest weaknesses I've seen from startups is not having a clear idea of what they're building, or not being able to express the idea clearly. You may need to change the idea as you reach new stages, but you always need a clear vision of what you're company is doing right now.
We appreciate your response and will try our best