#shorts
Launch LibreCAD and open the drawing that contains the entities you want to mirror.
Select the Mirror tool from the toolbar. It usually appears as two arrows pointing at each other.
Choose the entities you want to mirror by clicking on them. You can select multiple entities by holding down the Shift key while clicking.
Specify the mirror line. Click once to set the starting point of the mirror line, and then click again to set the endpoint. The mirror line defines the axis along which the entities will be mirrored.
Optionally, you can use the "Through" option to define the mirror line by selecting two points on the drawing. Click once to set the first point and then click again to set the second point.
Once the mirror line is defined, the selected entities will be mirrored or flipped accordingly.
If you want to mirror the entities as a copy instead of modifying the original entities, you can enable the "Copy" option in the tool options or use the Ctrl key while dragging the mirrored entities.
Continue using the Mirror tool as needed to mirror additional entities.