You must install this module via Magento Marketplace Or unzip it package under your root folder merging existing folders Admin After install, go to System > Configuration > Catalog > Catalog > Price.
And configure the decimal precision you want.
You can uninstall this module by removing all added files. No database update is necessary.
You can disable this module completely by editing app/etc/modules/Magenteiro_PriceDecimals.xml.
If you setup price decimals to 4, you will see 4 digits after decimal separator symbol, and can also use as price in product configuration. It will also affect price display in Invoices and Orders.