I would recommend to ask this Q at Stack Overflow community too:

https://stackoverflow.com/

There are already some similar Qs & As, for example:

https://stackoverflow.com/questions/30265728/in-r-base-plot-move-axis-label-closer-to-axis

@Anton Vrdoljak are these codes valid for Violin plot??

To Anmol Banerjee: Unfortunately, I do not have some great experience with R...

Hello Anmol Banerjee. I guess you are using ggplot. If so the following codes might be of use for you:

Remove background and gridlines:

+ theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank(), panel.background = element_blank(), axis.line = element_line(colour = "black"))

Title position:

+ theme(plot.title = element_text(hjust = 0.5))

hjust = 0.5 will place the title of your plot at the center. Therefore you just have to change this value.

Axis title:

+ opts(axis.title.x = theme_text(vjust = 0.5))

Again you have to change the vjust-value.

I hope this helps!

Best regards

Paul