A delivery note is not mandatory by law, but it is highly recommended for both the seller and the buyer. It serves as a record of the goods being delivered, providing details such as quantity, description, and condition of the items. This document can help prevent disputes or misunderstandings between the parties involved in the transaction. Additionally, a delivery note can also be used for inventory management and accounting purposes. **

Online teaching may be mandatory in certain situations, such as during a public health crisis when in-person instruction is not possible. However, in general, the decision to teach online is typically made by educational institutions or individual educators based on their specific circumstances and needs. Some institutions may require a certain percentage of courses to be offered online, while others may leave it up to the discretion of the instructor. Ultimately, the requirement for online teaching depends on the policies and guidelines of the specific educational institution. **

No, Nintendo Switch Online is not absolutely mandatory to enjoy playing games on the Nintendo Switch. While subscribing to Nintendo Switch Online provides access to online multiplayer features, cloud saves, and a selection of classic NES and SNES games, many games can still be played offline without a subscription. However, some games do require a Nintendo Switch Online subscription to access their online multiplayer modes. Ultimately, the decision to subscribe to Nintendo Switch Online depends on how important online multiplayer and the other features are to the individual player. **

A camera is not mandatory for online classes, but it can be helpful for certain activities such as virtual meetings, presentations, or group discussions where video communication is important. Some instructors may require students to have a camera for participation or engagement purposes, but in general, it is not a strict requirement. Students can still actively participate in online classes using just audio or text communication if they do not have a camera. **

A camera is not mandatory during online classes, but it can be helpful for engagement and participation. Some instructors may request that students have their cameras on to create a more interactive and engaging learning environment. However, there may be valid reasons for students to not have their cameras on, such as privacy concerns or technical limitations. Ultimately, it depends on the specific requirements and expectations set by the instructor or educational institution. **

The delivery of DHL Express within 24 hours is not mandatory for all shipments. DHL Express offers various delivery options with different transit times, including next-day delivery in some cases. However, the specific delivery time frame depends on the service level chosen by the shipper and the destination of the shipment. Customers can select the most suitable delivery option based on their needs and preferences. **

It is not mandatory to select an airplane seat online. Many airlines offer the option to select a seat during the online check-in process, but it is not required. Passengers can also choose their seat at the airport check-in counter or have a seat assigned to them at the gate. However, selecting a seat online can provide more options and ensure that passengers get their preferred seat. **

Retirement is not mandatory in most countries. It is a personal choice based on individual circumstances, financial readiness, and personal preferences. Some people choose to continue working past the traditional retirement age for various reasons, such as staying active, pursuing a passion, or maintaining social connections. However, some professions or industries may have mandatory retirement ages due to safety concerns or physical demands. **