As a supreme archer you have specialized in the way of bow and arrow, you can snipe enemies from longer ranges and do more bow attacks

Level 3: Improved Critical

Your attack rolls with ranged attacks can score a Critical Hit on a roll of 19 or 20 on the d20.

Level 3: Remarkable Athlete

Thanks to your athleticism, you have Advantage on Initiative rolls and Dexterity (Acrobatics) checks.

In addition, immediately after you score a Critical Hit, you can move up to half your Speed without provoking Opportunity Attacks.

Level 7: Defensive tactics

At 7th level you gain one of the following features of your choice.

 

25/20 vision

You are so precise that you gained blindsight

Multiattack defense

When a creature hits you with an attack, you gain a +5 bonus to your AC against all attacks from the same creature for the rest of the turn.

Predetermined dodge.

Ranged attacks against you are made with disadvantage.

Level 10: Rain of arrows

At 10th level you gain 2 of the following features of your choice.

Eagle sight

You gain the eyesight of an eagle. You can see up to 1 mile away with no difficulty, able to discern even fine details as tough looking at something no more than 100 feet away from you. Additionaly, all your normal and long ranges with ranged weapons are doubled.

Piercing arrows

You can roll one additional weapon damage die when determining the extra damage for a critical hit with a ranged attack. This increases to 2 additional dice at 13th level  and 3 additional dice at 16th level

Superior attacks

You gain 3 maneuvers of your choice. Your superiority die for them is a d10 at 10th level and turns into a d12 at 18th level.

The amount of superiority dice you have is equal to your proficiency bonus

Volley

You can use your action to make a ranged attack against any number of creatures within 10 feet of a point you can see within your weapon's range. You make a seperate attack roll for each target

Level 15: Superior Sniping

Your attack rolls with ranged weapons can now score a Critical Hit on a roll of 18–20 on the d20.

Level 18: Pinnacle of Archery

You attain the pinnacle of Archery in battle, giving you these benefits.

"For 1 minute, you have advantage on ranged attacks against enemy creatures and you have immunity against piercing damage. You can't use this feature again untill you have taken a long rest"

Or 

"For 1 minute, you gain true sight within a range of 50 feet and you automatically do all damage on ranged weapon damage die against a creature within you normal range. You can't use this feature again untill you have taken a long rest."

 

arrow evasion

For 1 minute, you have advantage on ranged attacks against enemy creatures and you have immunity against piercing damage. You can't use this feature again until you have taken a long rest.

True sniper

For 1 minute, you gain true sight within a range of 50 feet and you automatically do all damage on ranged weapon damage die against a creature within you normal range. You can't use this feature again untill you have taken a long rest.