No destination disk to install Mac OS to

What OS installer is booted? That is what OS option is there to install on the first screen? If you are booted to an older macOS installer such as 10.7 Lion, then you may not see any valid volumes because older versions of macOS don't understand the newer drive layout utilized by the APFS file system.

Try booting into Internet Recovery Mode using Command + Option + R to access the online macOS 10.13 High Sierra installer.....assuming that macOS 10.12.4+ was previously installed at some point in the past. If you boot to the High Sierra installer, then within Disk Utility you may need to click "View" and select "Show All Devices" before the physical drive appears on the left pane of Disk Utility. Select the physical drive and erase it as GUID partition and MacOS Extended (Journaled). If successful, then quit Disk Utility and select the "Install macOS High Sierra" option.

Unfortunately sometimes no matter which keys you use to access recovery mode, the Mac may only boot to the online installer for the OS which originally shipped with the Mac from the factory. If it is booted to a macOS 10.7 to 10.10 installer, then you need to partition & format the whole physical drive using the instructions in this article:

https://eshop.macsales.com/tech_center/formatting/Mac_Formatting_6-10_R3.pdf

FYI, if you can still boot this laptop to the internal drive, then I would highly recommend creating a bootable macOS 10.13 High Sierra USB installer now while you still can so you have more options since some people have issues with Internet Recovery Mode. Here is an Apple article with instructions:

Create a bootable installer - Apple Support

If you do not see the physical internal drive, then that drive has failed. It is possible the cable connection to the drive or Logic Board is loose so you can try reseating both connections to see if it makes any difference. There is a slim possibility that the internal HD SATA flex cable is bad (while the 2012 model was notorious for having bad cables, I never personally encounter a bad cable with the 2011 models). If the internal drive has failed, then it is possible to replace it with an SSD upgrade. A Crucial MX500 2.5" SSD is a good option (avoid the Crucial BX500 series as it is complete junk).

I'm assuming you have a MacBook Pro laptop here when I mention the cable issue & connections since like @John Galt mentioned there are no 2011 Mac Pro desktop towers.

Regardless if you have a laptop or a desktop tower, the internal hard drive has most likely failed. If you do have the desktop tower, then please let us know as it can possibly change some things.

Before you go too far, can you confirm your exact model Mac Pro? There is no 2011 model, but there are 2010 and 2012 models that can run Mojave provided it has a Metal-compatible graphics card.

There is no practicable way to install High Sierra any more (•), but as of this writing Mojave is still an option.

• There are tortured workarounds though...