You can use annotations, cursors, and drawn envelopes to highlight meaningful data points and regions on graphs.

Adding Annotations to Graphs
Use annotations on a graph to highlight data points in the plot area. The annotation includes a label and an arrow that identifies the annotation and the data point.
Adding Cursors to Graphs
Use a cursor on a graph to read the exact value of a point on a plot. The value at that cursor displays in the cursor legend that is associated with the graph.
Deleting Cursors from Graphs
Delete cursors from a graph with the cursor legend.
Drawing to the Graph Plot Area
You can customize the graph plot area of intensity graphs, mixed signal graphs, and waveform graphs by drawing a background image, middle image, or foreground image in the plot area.
Mapping Graph Coordinates to Plot Image Coordinates
By default, LabVIEW draws plot images relative to a plot area origin point. You can instead use data points of the graph as references rather than the plot origin by translating between coordinate systems.

Parent topic: Graph-Specific Configuration

LabVIEW User Manual