We have implemented a new Guild Levelling system in the latest update. Now, to increase your guild's level, you need no additional effort - just play the game actively: level up, defeat bosses, complete quests, and join other regular activities.
For any ingame activity that grants character experience, the guild will also earn it — including for 80 level characters.

Some important information: Each member contributes ~20% of the experience they earn to the guild's "treasury".
For example, if a level 80 guild member completes https://wowroad.info/?quest=12555 quest guild will receive 4441 experience points.

There is a global daily cap for guild experience - not more than 4 000 000 experience per day.

A detailed description of levels and their associated bonuses is available in the ingame menu (https://wowroad.info/?spell=38057). To open it, either type .menu command in a chat and navigate to the guild section or check the list below:

1 level (0 exp) - default level, no bonuses

2 level (16 000 000 exp): «Fast Track» (1 lvl)
Character experience increased by 3%.

3 level (17 500 000 exp): «Mount Up»
Increases speed while mounting by 3%. Not active on Battlegrounds or Arenas.

4 level (19 000 000 exp): «Honorable Mention» (1 lvl)
Increases Honor points gained by 3%.

5 level (20 500 000 exp): «Mr. Popularity» (1 lvl)
Reputation gained increased by 3%.

6 level (22 000 000 exp): «Reinforce» (1 lvl)
Items take 10% less durability loss when you die.

7 level (23 500 000 exp): «Mobile Banking»
Summons a Guild Chest that llows access to your guild bank for 5 minutes.
You can use the ability either from the personal game menu ".menu" (section "THE GUILD"), or with the command ".guild vault".

8 level (25 000 000 exp): «Fast Track» (2 lvl)
Character experience increased by 5%.

9 level (26 500 000 exp): «Honorable Mention» (2 lvl)
Increases Honor points gained by 5%.

10 level (28 000 000 exp): «Mr. Popularity» (2 lvl)
Reputation gained increased by 5%.

11 level (29 500 000 exp): «Reinforce» (2 lvl)
Items take 20% less durability loss when you die.

12 level (31 000 000 exp): «Hasty Hearth»
Reduces the cooldown on your Hearthstone by 15 minutes.

13 level (32 500 000 exp): «Have Group, Will Travel»
Summons all raid or party members to the character's current location. Cannot be used while in combat. Does not work in instances, Battlegrounds, Arenas, Wintergrasp and capitals of the races. To use this ability, you must have two guild members nearby who are in the same group/raid as you. The ability's cooldown applies to everyone who participated in calling and everyone who accepted the call.

You can use the ability either from the personal game menu ".menu" (section "THE GUILD"), or with the command ".guild call"..

14 level (34 000 000 exp): «Guild Mail»
Ingame mail sent between guild members now arrives instantly.

15 level (35 500 000 exp): «Instant Recharge»
After completing a dungeon encounter, all character abilities that have cooldown between 30 seconds and 20 minutes are recharged instantly. Debuffs blocking Bloodlust and Heroism are also removed. The guild perk only works in raid dungeons, and only if the fight lasted at least 30 seconds.

Also, the cooldown of the guild perk "Have Group, Will Travel" is halved.

16 level (37 000 000 exp): «Top Guild»
Upon reaching guild level 16, 5 https://wowroad.info/?item=20421 are awarded and 10% discount on all transactions with Guild Houses. Also, all characters are given a unique "Water globule" mount morph. Morph is only available to a character while he is member of level 16 guild.