Now complete guide of how to install ubuntu 19 in windows 10 is as follows

• Before starting your pre-installed with ” Windows 10 OS” or an older version of such as Windows 8.1 or 8.

•  you should first install Microsoft Windows and then proceed with Ubuntu installation.
•  Windows installation steps, you should allocate a free space on the disk with at least 20 GB in size for use it later as a partition for the “ Ubuntu 19.04 ” installation.

Requirements:

Download Ubuntu 19.04,Ubuntu 18.10, or Ubuntu

• Following Link for Downloading Ubuntu versions:

Select your required version of Ubuntu

• Ubuntu 19.04,
• Ubuntu 18.10,

 Select Download Option and also Ubuntu Desktop 19.04

Desktop image

            The desktop image allows you to try Ubuntu without changing your computer at all, and at your option to install it permanently later. This type of image is what most people will want to use.

Step 1: Create a live USB/disk of Ubuntu

Step 2: Make a partition where Ubuntu will be installed

            Lets assuming you have a fresh system, first, we need to make a partition to install    Linux(Ubuntu 19.04).

          If you have just one partition like this, you need to make some free space out of it for Linux(Ubuntu    19.04). If you have several partitions of considerable size, use any of them except C drive because it may erase the data.

            To make a partition in Windows 10, go to the Disk Management tool.

            In the Disk Management tool, right-click on the drive which you want to partition and select “shrink volume “. In my case, I shrank the C drive to make some free space:

Step 3: Install Ubuntu with Windows Dual-Boot

• The purpose of this article, We will be installing Ubuntu 19.04  with Windows dual boot (you can use any Ubuntu release fro installation).
• Create a bootable USB stick using a utility such as “Universal USB Installer” (BIOS compatible) or any utility software you know.
• Place the USB stick or DVD in the drive, reboot the machine and instruct the ”BIOS/UEFI” to boot-up from the DVD/USB by pressing a special function key (usually F12, F10 or F2 depending machine specifications).

• Install Ubuntu

 Choose the language you wish to perform the installation and click on Continue button 

 choose the first option “Normal Installation” and hit on Continue button

 choose the first option “Something” and hit on Continue button

• Create a partition for Ubuntu. We recommend that you create two partitions, one for root and the other for home accounts data.
•  The root partition, select the free space and hit on  + icon below. On partition settings use the following configurations and hit OK to apply changes:
• Size at least 20000 MB
• Type for the new partition  Primary
• Location for the new partition  Beginning
• Use as  EXT4 journaling file system
• Mount point /

Create the home partition:

• Size  all remaining free space
• Type for the new partition Primary
• Location for the new partition Beginning
• Use as  EXT4 journaling file system
• Mount point /home

select Install Now  :

Click continue:

Adjust your machine location by selecting a city nearby from the map. When done hit Continue.

 Fill username and password for your administrative,

Enter  Your name for your computer and Continue to finalize the installation.

After the installation process reaches its end hit on the Restart Now button in order to complete the installation.

Click Restart Now :

You have Successfully Installed Ubuntu with Windows 10. Press enter and continue.