Offers for Woocommerce is the only free plugin available for Woocommerce, where you can add Make Offer button to each Woocommerce product. Make offer form available in two methods, either you can set light box / add it to the tabs below Wocommerce product.
When you add Make Offer button to woocommerce catalog / archive page. It is set to float left. Check the screenshot below.
How to fix this?
It can be easily fixed by adding simple custom css to overwrite the original plugin css.
Just copy and paste the below css to your theme stylesheet (css file) or in custom css provided by Jetpack / theme option.
/* center the make offer buttons, offers for woocommerce */
If you want to add it in your theme css, then go to Appearance -> Editor by default it will be in CSS file (Style.css). If not select it from the right side list. Now copy the above css and paste it in the Style.css file.
That’s it, Now refresh the woocommerce archive / catalog page. It should work, If not try deleting the cache on cache plugins.