There are two ways to insert images into the content. If we want to just display an image at the top of the content, we can use the default image field of Drupal content types.
But to add images within content, we have to install 'insert' module.
You need to install the module and enable it.
Enable insert button and configuration by going to the image field setting for the content type (e.g. blog).
After enabled, now we can insert images using below steps.
Go to 'IMAGE' block of add content page, Choose File, Click Upload and after uploading the image, just click 'Insert', which will insert images within the content.
After uploading the image, click insert
This will insert the image to the specified location. We have to ensure that 'Full HTML' is selected for text format drop-down to display the image properly