Hello Vikaskumawat, Sorry for the late reply, it was a week-end here.
You can change the background color of the entire row by placing your blocks inside a Column block and change the column settings with the preferred image/color. Note that this will change the entire row background.
For centering the images below the divider, the best solution would be to place this image in a single block image; you can change the block option to align the image in center:
To place border around the image, this should be done before you upload the image on any picture editing software. There is no option in WordPress to put borders around images. This may also be achieved by placing some CSS code but it will apply on all images here.
I saw that you already removed the white space between text.
Let me know if I can help you any further.