The authorised share capital for an ADGM company is the maximum amount (in USD) of share capital that the company is authorised by its shareholders to issue to shareholders. The issued share capital is the portion of the authorised share capital that has been issued and is now held by the shareholders.
The company can issue the entire authorised share capital or hold back some as unissued shares to be issued to shareholders in the future. While the authorised share capital can be increased with shareholders' approval, this requires a filing with ADGM. We would therefore recommend that you don't issue the full authorised share capital at the time of incorporation so that you avoid this additional step and cost when you come to issue shares for the first time after incorporating the company.
By way of example, a company may have set its authorised share capital at USD 1,000, comprising of 10,000,000 shares of USD 0.0001 par value each. This means that the company can issue up to 10,000,000 shares before the shareholders will have to pass a resolution to increase the authorised share capital. The company may have issued 5,000,000 shares at the time of incorporation which means the company has retained 5,000,000 shares for future issue.
If, in the example above, the par value of each share was set at USD 1.00 each, then the Company would only have 1,000 shares that it can issue before needing to increase the authorised share capital.