If your motherboard supports it, it should be enabled by default. If it's not enabled and your motherboard does support it, then you can enable it by selecting the option from the BIOS menu. During boot up, press F2 to access the BIOS. Then, you should see an option that either says, "Boot from USB" or "Boot from External Device". Enable it by pressing enter and then selecting "Enable", If neither of these two options are available or something similar to it, then your motherboard does not support it.
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If your motherboard supports it, it should be enabled by default. If it's not enabled and your motherboard does support it, then you can enable it by selecting the option from the BIOS menu. During boot up, press F2 to access the BIOS. Then, you should see an option that either says, "Boot from USB" or "Boot from External Device". Enable it by pressing enter and then selecting "Enable", If neither of these two options are available or something similar to it, then your motherboard does not support it.