President Trump’s executive order:

On April 21, 2020, President Trump signed the executive order for the suspension of issuing immigrant visas abroad for 60 days.

It does not apply to those who are applying the green card in USA.

The order will apply to foreign nationals seeking a green card who are outside the United States at the time of the order, excluding from the suspension those who are in the country seeking to change their immigration status. Those who are applying adjustment of status (green card) in USA, are not included in this executive order. It only applies when you apply an immigrant visa (family based, or employment based) abroad.

Notably exceptions

It also carves out exceptions for essential workers, including medical personnel, spouses and children and parents of U.S. citizens, members of the Armed Forces, individuals designated by law enforcement, prospective foreign adoptees of U.S. citizens, and prospective "investor visa" users. Trump also noted Tuesday that the order would not apply to seasonal farm workers, who would seek seasonal guest worker visas.

It does not apply to all non-immigrant visas such as F-1, E-2, H1B, R-1 etc.

The hardest-hit category of immigrants will likely be those who seek green cards through their employers or on the basis of their professional merits as well as family based visa categories such as spouse and children of Permanent resident, son and daughter (married or unmarried: 21 years old and over) of USC, and brother and sisters of USC. But these categories take many years anyway.  For, practically all the US embassies are closed, and not processing any family based or employment based visas anyway due to Corona virus crisis.

No practical effects on immigration process but a political gamesmanship.

Practically this anti-immigration executive order does not accomplish anything. There is absolutely no relationship between immigration and Covid 19 infection in the US. I honestly believe that Trump's executive order is nothing but distraction for his failure to handle this corona virus crisis and political gamesmanship blaming and scapegoating immigrants and attempt to solidify his anti-immigrants political base.