When configuring scanning apps in the Udocx Admin portal, the 'Scan Settings' tab includes many options that may or may not be applicable to your particular make/model of MFP device. The tab allows you to configure the default scan options and whether or not those options are configurable by the user at scan time. The options are mostly self-explanatory: Color/black and white, resolution, single or double-sided, etc.
The last option is 'Job build' which can be enabled or disabled. This option controls how the MFP functions when a document is placed on the glass instead of in the document feeder. When enabled, a single Udocx job may be constructed from multiple scan operations. When disabled, only a single page will be scanned and immediately processed by Udocx without further confirmation. This behavior is MFP-specific and may not apply to your make/model of device. The default behavior of many devices is to function as 'Job build = enabled' and ignore this setting.