If the clothes you purchased originally did not have a trademark, it would not be considered an infringement. If the clothes originally had a trademark and you removed the trademark and put your own brand on it, then it would result in infringement. Trademarks can be used as long as they do not infringe the rights of others, but they are not protected by law, so it is recommended that you apply to register a trademark. Because registering a trademark can prevent others from using the same or similar trademark as yours, it is conducive to building a brand and increasing its popularity.