I want to register a trademark, Yifeng products are office furniture, but there is already a Yifeng

If it's in the same category, in the same group. Exactly the same characters and fonts they have registered.

Then even if you add one or two words before, after or in the middle, the possibility of being rejected or disputed later is very high.

Therefore, in order to reduce the risk, it is recommended that you change the trademark registration name. Being different from others is also good for your branding.

The determination of the similarity of trademarks mainly depends on whether the meaning of the main words of your trademark and the existing trademark is similar or the same, that is, whether the subject of the words is similar. For example, apples are similar to big apples, green apples, high-quality apples, etc., because the subject is all expressing apples, but some characteristics of apples are modified later, and the subject is still unchanged.

Therefore, if you add the word, the most important thing is whether the meaning of the word is similar to "Yifeng", if it is not similar, you can apply.

In other words, it's good that the meaning is different from Yifeng.