Downloading a Christian app is one way to promote the modern Christian movement.
That supports Christian app developers.
What can be achieved today to promote the modern Christian movement? Download a new Christian app. That supports Christian app developers. It also promotes that sector of the industry.
If every Christian in this country downloaded a new Christian app today, the number would be in the millions. Many of those apps are free. You could download one now if you wanted.
What about promoting Christianity offline? After putting your phone in your pocket, consider putting on a Christian sweatshirt if you have one, to wear wherever you may be going. Imagine seeing even two or three people wearing clothing that says, "I love Jesus" at the grocery story or in the mall. It is a simple, effective way to create a real public presence.