Please see: https://easyeda.com/forum/topic/How_does_the_Connect_Pad_to_Pad_tool_work_-JgQO0Ay7H

hi The single pad can't be connected by ratline, only the footprint's pad can use the tool "connect pad to pad"

I appreciate that, as above link states, it's better practice to use footprints converted from schematic, but often the footprint isn't available. Anyway, I worked out you can still connect a track to a single pad, so I'll continue doing it that way. Thanks.

EasyEDA is flexible enough to allow you to connect arbitrary pads just using the copper track tool and snapping them to pads but it is better to use the `Connect Pad to Pad` tool on defined PCB footprints: you get more useful information - such as readable netlabels - out of the Design Manager that way. Better still is to start with a schematic with all the package and BoM information added into it and checked using the Schematic Design Manager. Then you can check - and if necessary create any missing - PCB footprints and then convert straight to PCB with no errors.