The Toe angle adjusts the angle of the tyres pointing inward towards, or outward away from, the centre line of the car when viewed from a top-down perspective.
For the front toe angles, using negative values (Toe-Out and pointing the leading edge of the tyres away from each other) will improve responsiveness and cornering ability, but makes the car less stable in a straight line. A value between max negative front toe angle and -0.15 is preferred.
For the rear toe angles, using negative values will increase rotation (oversteer) from the rear tyres, but may cost you traction when powering off the turn. Postive values will increase rear end grip and provide greater stability coming off corners. A value between -0.10 and +0.15 depending on track, car and personal preference is ideal for rear toe angles.
More negative or positive Toe Angle will have an effect on tyre temperatures and tyre wear. The more negative or positive the Toe Angle, the more the tyres will scrub across the track surface, generating more heat and increasing wear. Prioritise car performance / handling over temperature and wear, unless it is excessive and impacting car performance over a longer stint duration.