Is there anyway to edit the measurement scale and align. With the Measure tool i can just scale the mesh. If i want the exact size i cant edit it. For example i need 7.0. With the tool it not fixing the exact value. Going beyond 7 or below. Hope i can edit the value and then align mesh. Any suggestion or help.
Press N to bring up a side panel. With a target edge/vertex selected, go to Item and adjust the position of it using the fields shown below. Press and hold LMB to use slider, single press to enter a value. Note that you can enter math expressions, so entries such as -1 + 52 / 2 or 10m - 5cm are completely valid.
The amount you want to change the length by will be the amount you will need to change the location in the corresponding axes. In this case, I've extended the length of the rectangle below by 2.75 ft by moving the Y-axis position of the edge by 2.75 ft
Depending on the orientation of your object, you may need to add or subtract to the value for the X, Y or Z axis.
Blender is not a CAD software, you cannot change the object data with the measure tool. You might be able to with some other add-on but this is not possible with the "vanilla" measure tool.
As explained in the other answer you can achieve this by other means. To answer your question, this is currently not possible.