The trim command will erase a part of an object up to a boundary. All objects are considered boundaries.

1) Activate the trim command by selecting the Trim button OR by typing in "trim" and hitting enter

2) Hover over a part of the object to be erased and it will preview which portion will be trimmed

3) Click on the portion of the object to be trimmed

The extend command will lengthen an object up to a boundary. All objects are considered boundaries.

1) Activate the extend command by selecting the Extend button OR by typing in "extend" and hitting enter

2) Hover over a part of the object to be lengthened and it will preview which portion will be extended

3) Click on the portion of the object to be extended