At the present moment, those looking for Windows Forms jobs in Mexico City will find only a rather small variety. There are just 6 job offers on Jobspotting as it stands. .NET Framework or Microsoft APIs jobs are overarching themes worth a look, as these are the main categories the job offers can be broken down to. Jobs that require .Net, C#, or Microsoft Visual Studio are often seen in job offers in this area.
This is not the best time to search for Windows Forms internships. Companies are now almost exclusively recruiting capable candidates. There aren't currently any startups in the current companies on Jobspotting looking for Windows Forms competency. Have you seen which other skills are in demand in this region?