Who can participate in a public tender?
Public tenders, let's see, are like those powers where the Government puts the rules and companies fight (in good wave, of course) to see who stays with the fat contract. Basically, if you have a well -armed company, following the laws of the country and fulfilling all the paperwork, you already have half a ticket.
Of course, it is not enough to exist in the Mercantile Registry and have your RFC in order. You have to have a money (or at least access to credit), technical muscle and experience. That is, nobody wants the cousin of a friend who has never built a little house comes to raise a hospital. They always ask you to show your finances, previous jobs and some paper that says "I do know how to do this."
Now, from time to time, those who organize the tender are exquisite: they want companies with years of experience, quality certifications, or that are super green and responsible. All that comes in the bases, so you better read them with magnifying glass, because if you do not meet, or bother to apply.
Ah, and eye if you are a foreigner. Not everywhere they let you participate so easy. Sometimes they ask for local partners or simply tell you "thank you, but not thanks." So if you are from outside, investigate well before getting excited.
In summary: anyone who has a legal company, with silver, experience, and that fulfills the whims they ask for in the bases, can be launched to compete. But, the net, if you don't know what the thing is about or you don't have to answer, better or mess. Read everything, ask a thousand times and make sure you can fulfill before throwing yourself into the ring.