Get Enumeration Type
You can get an IEnum object from an enumeration name by using the GetEnum method of the IMetamodels object.
public void GetEnum(ICommandContext c, ICommandParams p)
{
    //Get the metamodels
    IMetamodels metamodels = c.App.Workspace.CurrentProject.Profile.Metamodels;
    var en = metamodels.GetEnum("RequirementType");
    //Print the display name of the enumeration
    c.App.Output.WriteLine("sample", $"Enum: {en.DisplayName}");
    //Print the literal of the enumeration
    foreach (var literal in en.Literals)
    {
        c.App.Output.WriteLine("sample", $"Literal: {literal.DisplayName} ");
    }
}