Develop Reference

Loading page after displaying the Unity logo at the beginning of the game

I plan to open the banner immediately after the player opens the game and the Unity logo is seen and display it for a while and then enter the game. Please help me how to put my banner?
I expect this answer to solve this problem

If by banner you mean a title screen / main menu, then you just need to create a Scene for it. Not exactly sure what else you're asking here.
For creating a scene: https://docs.unity3d.com/Manual/scenes-working-with.html
For creating specifically a title screen, there's plenty of YouTube tutorials to help you with that.

Go to Edit -> Project settings -> player
Then navigate to Splash Image -> splash screen
You can then add any image you like and modify how long is it onscreen for
Here is the docs page

Close splash screen in Hololens 2 with unity

I am a new in Hololens 2 and I build some Unity sample on it.
When start application, it would placed a white box like that.
When stop application, the white box still on here and I need to click X to close it.
I have searched about that, it seem like about uwp application lifecycle?
Is there any method to close it with C# when I quit my application.
Thanks in advance for any suggestions.

It is by design and can only be closed manually, every app starts in mixed reality by placing an app tile in the Windows Mixed Reality home and these tiles persist and stay at their placed location. For more information please see:App model
In addition to this, you can add a custom holographic splash screen for the app, please refer to this link:Holographic splash screen

Setting Screen to Format on all Windows PC sizes

The game looks fine inside the Unity screen view, but if I build and choose a different resolution screen size the game looks goofy and dis-proportioned. Especially when I go into full screen mode. I'm using Unity 2019.1.1a (I think it's still in beta?). I'm developing a top down 2D game for Windows PC.
How can I fix it to where the game will look the same on any screen size?

Unity has some good tutorials on this topic:
https://unity3d.com/es/learn/tutorials/topics/user-interface-ui/ui-tools-resolution-device-independence
https://docs.unity3d.com/Manual/HOWTO-UIMultiResolution.html

XNA - Showing a texture without a window?

I wanted to know whether it's possible to show a 2D Texture in XNA without a window that contains it. Just like drawing a picture/texture (maybe with the SpriteBatch.draw()-method?) simply onto the screen, independent from a seperated window. (What comes to my mind here is the Photoshop-opening window)
Is this possible in XNA? I can't find anything like this for SpriteBatch. Do I have to write totally new code/method?

If you mean splash image, it might be drawn from another application before launch (aka launcher) or you can show border-less window with image while loading application content in background.
Unfortunately XNA does not support border-less window, however there is walk-around using windows forms: https://gamedev.stackexchange.com/questions/37109/is-there-a-simpler-way-to-create-a-borderless-window-with-xna-4-0
If you will be able to create borderless window with XNA, then you need to change window size in constructor to splash image size, and draw same size image while loading content.
I would not recommend displaying splash image as it serves no real purpose, if you want to display some logo while starting the game - simply start game in fullscrean and draw image on black background while loading content, this is the way all modern games does it.

Orientation issue in windows8 metro app.

I am currently working on widows8 metro app tablet version.In My package.appmanifest file I have choose supported rotation as landscape.but when iam launching the applicaiton by holding the device in portrait mode.For fraction of seconds splash screen is coming in portrait mode and then it changed to landscape.
can anyone know how to solve this problem. because of this issue i am facing other issues.

You can add your custom splash screen. If your application only supports landscape, you could make your splash screen appear in landscape by manually adjusting the image to load.
Another option could be to make an extended splash screen. This way, you can programatically make your splash screen appear for say, a second or so.
Check this article from Microsoft, Creating a fast and fluid app launch experience, which has examples and information about extended splash screens.